There are two parts to an egg and they cook slightly differently. The yolk takes longer to cook than the white partly because it is insulated more and there is less protein in it.

Boiling an egg is therefore a balancing act, and you will not always get it right.

Before boiling make sure your egg is at room temperature, not straight from the fridge. It is best to store eggs on the worktop most of the time, though they will refrigerate well.

For a medium sized egg, place it in boiling water and cook for 3 1/2. This will give you a runny yolk and a generally set white, though if your eggs are cold to start with add another 30 seconds.

4 1/2 minutes will give you a very set white and a partly runny yolk.

For hard boiled eggs, place them in cold water and bring to the boil and cook for 6 to 7 minutes, longer if you want them really very hard boiled, up to 10 minutes.

To stop the cooking of hard boiled eggs, plunge them into cold water, which will remove the excess heat. This is fine for salad eggs, or eggs to be used in pies and other dished. However, you want a breakfast egg good and hot.

Stopping the cooking of a hard boiled egg will also reduce the occurrence of the dark line between the you and the white. The line is iron sulphide, and quite harmless, but does look a little unsightly.